RESUMO
Growing evidence shows that antioxidant proteins of Leishmania could be used as vaccine candidates. In this study, we report the efficacy of Leishmania donovani iron superoxide dismutase B1 (LdFeSODB1) as a vaccine antigen in BALB/c mice in a DNA-protein prime-boost immunization regimen in the presence or absence of murine granulocyte macrophage colony stimulating factor (mGMCSF) DNA adjuvant. The expression study confirmed that LdFeSODB1 is expressed in mammalian cells and mGMCSF fusion mediates the secretion of the recombinant protein. Heterologous immunization with LdFeSODB1 induced a strong antibody- and cell-mediated immune response in mice. Immunization triggered a mixed Th1/Th2 response as evidenced by the ratio of IgG2a to IgG1. Antigen-stimulated spleen cells from the immunized mice produced high level IFN-γ. Multiparametric flow cytometry data showed that immunization with LdFeSODB1 induced significantly higher expression of TNF-α or IL-2 by antigen-stimulated T cells. Eight weeks after L. major infection, immunization with the antigen shifted the immune response to a more Th1 type than the controls as demonstrated by IgG2a/IgG1 ratio. Moreover, IFN-γ production by antigen-stimulated spleen cells from immunized mice remained high. The footpad swelling experiment showed that immunization with LdFeSODB1 resulted in partial protection of mice from a high dose L. major infection.
Assuntos
Leishmania donovani/imunologia , Proteínas de Protozoários/imunologia , Vacinas Protozoárias/imunologia , Proteínas Recombinantes/imunologia , Superóxido Dismutase/imunologia , Vacinas de DNA/imunologia , Animais , Citocinas/análise , Citocinas/genética , Citocinas/metabolismo , Feminino , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/prevenção & controle , Proteínas Luminescentes/análise , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Vacinas Protozoárias/química , Vacinas Protozoárias/genética , Vacinas Protozoárias/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Superóxido Dismutase/química , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Vacinas de DNA/genética , Vacinas de DNA/metabolismoRESUMO
In this study, we tested the protective efficacy of recombinant Leishmania donovani iron superoxide dismutase B1 (SODB1) against Leishmania major infection in BALB/c mice. Mice were challenged with L. major 3weeks after the second boost immunization with rSODB1 alone or in the presence of adjuvants. Injection of BALB/c mice with rSODB1 alone elicited both humoral and cellular immune responses. Administration of rSODB1 with CpG ODN or GLA-SE (a synthetic toll-like receptor 4 agonist) adjuvant resulted in the induction of anti-SODB1 IgG1, and more importantly of significantly high levels of IgG2a isotype. Immunization of mice with rSODB1 alone or with adjuvant induced the production of IFN-γ by splenocytes in response to stimulation with L. major soluble leishmanial antigens (SLA). Moreover, immunization protocols involving rSODB1 resulted in a significant decrease in IL-10 as compared to controls. The presence of CpG ODN or GLA-SE adjuvant in the immunization protocols resulted in a relative increase in IFN-γ in response to stimulation with rSODB1 in comparison to immunization with rSODB1 alone. Mice immunized with rSODB1 plus CpG ODN or GLA-SE, were able to partially control their Leishmania infections, as indicated by the reduction in footpad swelling and parasite numbers, compared to controls. These results suggest that immunization with recombinant SODB1 protein together with CpG ODN or GLA-SE can be potential vaccine candidate against leishmaniasis.